Domestic gas ball stopcock with elastomer, e.g. PTFE, seals - comprising seal-carrying rings making sec. seal by sealant inflating above 100 deg.C stable to 650 deg.C to prevent leakage in case of fire

摘要

In a ball stopcock seal, elements (22) consist of high-temp. resistant carrying rings (41, 42) with elastomer (SIC) inserts (47), pref. of PTFE, seating on the ball (14). An annular groove on the back side of rings (41, 42) is filled with a sealing material (49) which inflates at a temp. above 100 deg.C and is temp. resistant up to 650 deg.C. USE/ADVANTAGE - Domestic stopcock for gas supply. Retains the usual good sealing and easy movement at normal temps.; in the event of fire, the sealing material inflates (49) before the PTFE softens at about 250 deg.C, forcing the heat resistant rings (41, 42) into direct contact with the ball to maintain the seal. This avoids gas leakage, which could cause a gas/air mixt. leading to a space-explosion.